SE542330C2 - A method and a system for controlling an articulated vehicle - Google Patents

Abstract

The invention relates to method for controlling an articulated vehicle (1), the articulated vehicle (1) comprising: a front vehicle section (4) and a rear vehicle section (6); an articulation unit (8) allowing the front vehicle section (4) and the rear vehicle section (6) to pivot in relation to each other; and a damping arrangement (30) arranged to control the pivotal movement about the articulation unit (8). The method comprising the steps of: a) determining if the articulated vehicle (1) is about to collide with an external object; and if so b) applying a braking force on the articulated vehicle (1); and c) controlling the damping arrangement (30), such that pivotal movement about the articulation unit (8) is restricted. The invention also relates to a system (100) for a vehicle (1).The invention also relates to an articulated vehicle (1) comprising such a system (100).

Description

A METHOD AND A SYSTEM FOR CONTROLLING AN ARTICULATED VEHICLE TECHNICAL FIELD The invention relates to a method for controlling an articulated vehicle, a computer program, a computer-readable medium, a system and an articulated vehicle comprising such a system.

BACKGROUND AND PRIOR ART Articulated vehicles, such as buses, articulated lorries and trailer trucks, comprise an articulation unit connecting a front vehicle section with a rear vehicle section and enabling the two vehicle sections to pivot in relation to each other. One example of articulated buses is the so called pusher bus, which has a rear driving axle and the propulsion unit arranged at the rear vehicle section. Many challenges come with this type of design as it makes the weight of the vehicle uneven with a great amount of weight in the rear vehicle section on the driving axle, leaving the middle axle with less weight, pressure and grip. This construction may lead to a risk of the bus being folded when making a turn with the vehicle or when driving downhill on a slippery slope. This construction may also lead to general instability of the whole vehicle, especially at high speeds.

Various ways of monitoring and controlling articulated vehicles are today known for reducing the risk for dangerous situations. To prevent an articulated vehicle from being folded and to ensure that the vehicle is stable, a damping arrangement may be arranged in association with the articulation unit.

Document WO2010107370 A1 discloses a damping system for articulated vehicle and a method for regulating such a damping system. In a normal state, when there is no risk situation with regard to mutual outswing between a forward vehicle element and a rear vehicle element of the vehicle, a damping means of the damping system are caused to exert a damping force which is pulsated, in order thereby to facilitate mutual straightening up between the forward vehicle element and the rear vehicle element. When it is determined that there is a risk situation with regard to mutual outswing between the forward vehicle element and the rear vehicle element, the damping means are caused to exert a damping force which is non-pulsated and stronger than the damping force in the normal state, in order thereby temporarily to prevent the articulation angle from increasing, after which the damping means are caused to revert to the normal state with pulsated damping force of reduced strength.

SUMMARY OF THE INVENTION The damping arrangement in association with the articulation unit in an articulated vehicle may be controlled in order to stabilise the front vehicle section and the rear vehicle section in relation to each other. The damping provided by the damping arrangement may be controlled during the operation of the articulated vehicle and adapted to different situations. However, a specific situation that may occur is that the articulated vehicle is about to collide with an external object. Depending on how such situation is avoided, the front vehicle section and/or the rear vehicle section may pivot in relation to each other and causing a dangerous situation.

Therefore, it is a need to develop a method and a system for controlling an articulated vehicle when the articulated vehicle is about to collide with an external object.

An object of the present invention is therefore to achieve a new and advantageous method and a system for controlling an articulated vehicle when the articulated vehicle is about to collide with an external object.

The herein mentioned objects are achieved by a method for controlling an articulated vehicle, a system for controlling an articulated vehicle, an articulated vehicle, a computer program and a computer-readable medium according to the appended claims.

It would be advantageous to achieve a method and a system for controlling an articulated vehicle overcoming, or at least alleviating, at least some of the above mentioned drawbacks. In particular, it would be desirable to enable a method and a system for controlling an articulated vehicle when the articulated vehicle is about to collide with an external object. To better address one or more of these concerns, a method and a system for controlling an articulated vehicle having the features defined in the independent claims are provided.

According to an aspect of the invention the method for controlling an articulated vehicle may comprise a front vehicle section and a rear vehicle section, an articulation unit, which may allow the front vehicle section and the rear vehicle section to pivot in relation to each other, and a damping arrangement, which may be arranged to control the pivotal movement about the articulation unit. The method may comprise the steps of: a) determining if the articulated vehicle is about to collide with an external object; and if so b) applying a braking force on the articulated vehicle; and c) controlling the damping arrangement, such that pivotal movement about the articulation unit is restricted.

By such a method the articulated vehicle may be controlled when the articulated vehicle is about to collide with an external object. If it is determined that the articulated vehicle is about to collide with the external object, a braking force may be applied on the articulated vehicle. The braking force may reduce the speed of vehicle and stop the vehicle before the vehicle collides with the external object. When the braking force is applied also the damping arrangement may be controlled, such that pivotal movement about the articulation unit is restricted. By restricting the pivotal movement about the articulation unit the rear vehicle section may not pivot in relation to the front vehicle section when the braking force reduces the speed of vehicle. For this reason the rear vehicle section may not pivot and move out of the direction of travel. If the rear vehicle section should pivot and move out of the direction of travel, the rear vehicle section may end up in the opposite lane, which may lead to a collision between the rear vehicle section and an oncoming vehicle. Also, a jack-knifing situation may be avoided by means of the method.

According to a further aspect of the invention the determination if the articulated vehicle is about to collide with an external object is based on a detection of the external object by means of a first sensor element arranged on the articulated vehicle. Such sensor element may be arranged on the front part and rear part of the articulated vehicle. The first sensor element may be a radar arrangement, a LIDAR, a camera and/or a GPS sensor. The first sensor element may also be an ultrasonic proximity detector, an electromagnetic sensor, a blind spot monitor or the like. When the first sensor element detects the external object, information about the detection may be sent to an electronic control arrangement. The electronic control arrangement may process the information and determine if the articulated vehicle is about to colliding with the external object.

According to an aspect of the invention the braking force may be applied automatically. When it is determined that the articulated vehicle is about to collide with an external object the braking force acting on the articulated vehicle may be applied automatically. The braking force may be applied by a brake arrangement acting on at least one wheel, on at least one drive axle and/or on a propeller shaft. The braking force may be automatically applied by means of an actuator acting on a braking pedal or directly on the brake arrangement acting on the at least one wheel, on the at least one drive axle and/or on the propeller shaft. Also, the braking force may be automatically generated by a propulsion source of the vehicle.

According to an aspect of the invention the amount of the applied braking force may depend on the speed of the articulated vehicle, the weight of the articulated vehicle; the current load distribution of the articulated vehicle and/or road condition. If the speed is high, the applied braking force may be high, so that the braking force may reduce the speed of vehicle and stop the vehicle before the vehicle may collide with the external object. If the weight of the articulated vehicle is high, the applied braking force may be high, so that the braking force may reduce the speed of vehicle and stop the vehicle before the vehicle may collide with the external object. If the current load distribution of the articulated vehicle is uneven, the amount of the applied braking force may be different for different wheels and drive axles, so that the braking force may effectively reduce the speed of vehicle and stop the vehicle before the vehicle may collide with the external object. If the road condition is clean and free from snow or ice, the applied braking force may be high, so that the braking force may reduce the speed of vehicle and stop the vehicle before the vehicle may collide with the external object. The speed of the articulated vehicle, the weight of the articulated vehicle; the current load distribution of the articulated vehicle and/or road condition may be detected by means of a second sensor element.

According to an aspect of the invention the controlling of the damping arrangement depends on the amount of the applied braking force. If the applied braking force is high, the damping arrangement may be so controlled that the restriction of the pivotal movement about the articulation unit is high. The high braking force applied on the articulated vehicle may result in a high reduction of the speed of the vehicle. In order to avoid that the rear vehicle section may pivot and move out of the direction of travel a high damping force applied on the articulation unit by the damping arrangement may restrict the pivotal movement about the articulation unit. Thus, both a jack-knifing situation may be avoided and a collision between the rear vehicle section and an oncoming vehicle, due to that the rear vehicle section may end up in the opposite lane, may be avoided.

According to an aspect of the invention the damping arrangement is controlled to restrict the pivotal movement about the articulation unit when the amount of the braking force is over a predetermined threshold value. The more braking force acting on the articulated vehicle, the more restriction of the pivotal movement about the articulation unit may be needed in order to avoid a jack-knifing situation and/or a collision between the rear vehicle section and an oncoming vehicle. However, if the braking force is at a level under a predetermined threshold value a pivotal movement about the articulation unit may not appear during the speed reduction of the articulated vehide. The threshold value may also depend on the the weight of the articulated vehicle, the current load distribution of the articulated vehicle and/or road condition.

According to an aspect of the invention the method further comprises to inform an operator of the vehicle of the determination that the articulated vehicle is about to collide with an external object.

Such information to the operator or driver may be an indicating signal on instruments in the driver's compartment. The indicating signal may be in form of a text message, a light signal, a sound signal and/or a haptic signal, such as vibrations conveyed to and sensed by the driver. The operator or driver may as a result of the information be prepared for the situation that the articulated vehicle may collide with an external object. As a result, the operator may apply a braking force on the vehicle in order to reduce the speed of vehicle and stop the vehicle before the vehicle may collide with the external object. When the braking force is applied also the damping arrangement may be controlled, such that pivotal movement about the articulation unit is restricted. By restricting the pivotal movement about the articulation unit the rear vehicle section may not pivot in relation to the front vehicle section when the braking force reduces the speed of vehicle. For this reason the rear vehicle section may not pivot and move out of the direction of travel. If the rear vehicle section should pivot and move out of the direction of travel, the rear vehicle section may end up in the opposite lane, which may lead to a collision between the rear vehicle section and an oncoming vehicle. Also, a jack-knifing situation may be avoided by means of the method.

According to a further aspect of the invention the method comprises the further step of: d) controlling the damping arrangement, such that pivotal movement about the articulation unit may be allowed if a steering angle of a steering wheel is detected.

If the operator or driver of the vehicle aims to avoid a collision with the external object by braking the articulated vehicle and at the same time try to steer away from the external object the damping arrangement may be controlled so that the pivotal movement about the articulation unit may be allowed. Otherwise, if the pivotal movement about the articulation unit is restricted the turning ability of the articulated vehicle may be restricted. Therefore, if a steering angle of a steering wheel is detected during the braking force is applied on the articulated vehicle, the damping arrangement may be controlled so that the pivotal movement about the articulation unit may be allowed.

According to a further aspect of the invention, a system for controlling an articulated vehicle is provided. The vehicle may comprise: a front vehicle section and a rear vehide section; an articulation unit allowing the front vehicle section and the rear vehicle section to pivot in relation to each other; and a damping arrangement arranged to control the pivotal movement about the articulation unit; wherein the system may comprise a control unit. The control unit may comprise: means for determining if the articulated vehicle is about to collide with an external object; and if so means for applying a braking force on the articulated vehicle; and means for controlling the damping arrangement, such that pivotal movement about the articulation unit may be restricted.

A control unit is to be interpreted herein as a unit comprising control logic capable of exchanging digital data with other control units. The control unit may comprise a single control unit or a plurality of control units.

The means for determining if the articulated vehicle is about to collide with an external object; and if so means for applying a braking force on the articulated vehicle; and means for controlling the damping arrangement, such that pivotal movement about the articulation unit may be restricted, may e.g. be different software modules/portions in the control unit, program code, algorithms or similar.

It will be appreciated that all the embodiments described for the method aspect of the invention are also applicable to the system aspect of the invention. That is, the control unit of the system for controlling an articulated vehicle may be configured to perform any one of the steps of the method according to various embodiments described herein.

Further objects, advantages and novel features will become apparent to one skilled in the art from the following details, and also by putting the invention into practice. Whereas embodiments are described below, it should be noted that it may be not restricted to the specific details described. Specialists having access to the teachings herein will recognise further applications, modifications and incorporations within other fields, which are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Below is a description of, as examples, embodiments with reference to the enclosed drawings, in which: Fig. 1 schematically illustrates an articulated vehicle according to an embodiment Fig. 2 schematically illustrates a system for controlling an articulated vehicle according to an embodiment, Fig. 3 illustrates a flow chart for a method for controlling an articulated vehicle according to an embodiment, and Fig. 4 schematically illustrates a control arrangement or computer according to an embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS The term “link” refers herein to a communication link which may be a physical connection such as an opto-electronic communication line, or a non-physical connection such as a wireless connection, e.g. a radio link or microwave link.

Fig. 1 schematically illustrates a side view of a wheeled articulated vehicle 1 according to an embodiment. The exemplified vehicle 1 is an articulated bus in the shape of an accordion bus. The vehicle 1 comprises a propulsion unit 2 for driving the vehicle 1, a front vehicle section 4 and a rear vehicle section 6. The propulsion unit 2 may be a part of a power train 3 also comprising a gearbox 5. The vehicle 1 further comprises an articulation unit 8 arranged to connect the front vehicle section 4 and the rear vehicle section 6 and to allow the two vehicle sections 4, 6 to pivot in relation to each other. The front vehicle section 4 comprises a front axle 10 with front wheels 12. The vehicle 1 has a steering wheel 7 connected to the front axle 10 and the front wheels 12. The front wheels 12 may thus be referred to as steered wheels 12. By turning the steering wheel 7 and thereby changing the steering angle a corresponding change in the front wheels 12 will be generated. By turning the steering wheel 7 a steering angle of a steering wheel may be detected by means of a steering angle sensor 13. The vehicle 1 further comprises an intermediate axle 14 with intermediate wheels 16. The intermediate axle 14 is arranged on the front vehicle section 4 in front of the articulation unit 8. The rear vehicle section 6 comprises a rear axle 18 with rear wheels 20. The rear axle 18 may be directly connected to the propulsion unit 2 and is thus a drive axle. The rear axle 18 may as an alternative be connected to the propulsion unit 2 by means of a propeller shaft 15. The rear wheels 20 may thereby be referred to as driving wheels 20, which may be connected to the power train 3. The vehicle may be provided with a brake arrangement 21 which may be arranged at the wheels 12, 16, 20, the axels 10, 14, 18 or the propeller shaft 15.

The propulsion unit 2 of the vehicle 1 may be arranged at the rear vehicle section 6. The vehicle 1 may thus be referred to as a pusher bus. The configuration with the propulsion unit 2 at the rear end of the vehicle 1 makes more room for passengers and a better distribution of the passengers in the bus. Challenges does, however, come with this type of design as it makes the weight of the vehicle 1 uneven with a great amount on the driving axle 18, leaving the intermediate axle 14 with less weight, pressure and grip. This may increase the risk of instability in and/or jack-knifing the vehicle 1 when applying a braking force on the articulated vehicle 1 in order to avoid a collision with an external object 17. The vehicle 1 may comprise a damping arrangement 30 arranged to control and restrict the pivotal movement about the articulation unit 8. The damping arrangement 30 may comprise at least one damping element 32 and a damping control arrangement 34 for controlling the damping effect of the damping elements 32. The at least one damping element 32 may be a hydraulic damping element 32. However, another kind of damping element 32 is also possible, for example an electric damping element 32 or a friction damping element 32, such as a disc brake.

The vehicle 1 may further comprise a system 100 for controlling an articulated vehicle 1 . The system 100 may comprise a control arrangement 200, which may comprise the damping control arrangement 34 of the damping arrangement 30 or any other control arrangement associated with the vehicle 1.

Fig. 2 schematically illustrates a system 100 for controlling an articulated vehicle 1 according to an embodiment. The system 100 may be adapted for controlling an articulated vehicle 1 as disclosed in Fig. 1. The system 100 may comprise a control arrangement 200. The control arrangement 200 may comprise: means for determining if the articulated vehicle 1 is about to collide with an external object 17; and if so means for applying a braking force on the articulated vehicle 1 ; and means for controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 may be restricted. The means for determining if the articulated vehicle 1 is about to collide with an external object 17; and if so means for applying a braking force on the articulated vehicle 1 ; and means for controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 may be restricted, may e.g. be different software modules/portions in the control arrangement 200, program code, algorithms or similar.

The system 100 may comprise first sensor element 210 arranged in communication with the control arrangement 200. The control arrangement 200 may be arranged in communication with the first sensor element 210 via a link L210. The first sensor element 210 may comprise a plurality of sensors. The first sensor element 210 may comprise sensors for detection of the external object 17. The first sensors means 210 may be arranged in communication with the control arrangement 200 via other control arrangements or via a CAN bus or similar. The first sensor element 210 may be a radar arrangement, a LIDAR, a camera and/or a GPS sensor. The first sensor element 210 may also be an ultrasonic proximity detector, an electromagnetic sensor, a blind spot monitor or the like. Based on signals from the first sensor element 210 the control arrangement 200 may automatically determining if the articulated vehicle 1 is about to collide with the external object 17; and if so b) applying a braking force on the articulated vehicle 1 ; and c) controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 is restricted.

The system 100 may further comprise second sensor element 220 arranged in communication with the control arrangement 200. The control arrangement 200 may be arranged in communication with the second sensor element 220 via a link L220. The second sensor element 220 may comprise a plurality of sensors. The second sensor element 220 may comprise sensors for identifying the speed of the articulated vehicle1. The second sensor element 220 may comprise sensors for identifying the weight of the articulated vehicle 1. The second sensor element 220 may comprise sensors for identifying the current load distribution of the articulated vehicle 1. The second sensor element 220 may comprise sensors for identifying the road condition.

The second sensor means 220 may be arranged in communication with the control arrangement 200 via other control arrangements or via a CAN bus or similar.

The control arrangement 200 of the system 100 may be arranged in communication with the brake arrangement 21 of the vehicle 1. The control arrangement 200 may be arranged for communication with said brake arrangement 21 via a link L21. The control arrangement 200 may be adapted to control the brake arrangement 21 in order to brake the articulated vehicle 1.

The control arrangement 200 of the system 100 may be arranged in communication with the damping arrangement 30 of the vehicle 1. The control arrangement 200 may be arranged for communication with said damping arrangement 30 via a link L30. The control arrangement 200 may alternatively constitute a control arrangement of the damping arrangement 30. The control arrangement 200 may be adapted to control a pivotal movement about an articulation unit 8 of an articulated vehicle 1 as disclosed in Fig. 1. The control arrangement 200 may thus be adapted to control at least one damping element 32 arranged to dampen a pivotal movement about the articulation unit 8, such that the pivotal movement about the articulation unit 8 is restricted. The control arrangement 200 may be adapted to control at least one proportional valve unit 36 arranged to regulate the damping effect of the at least one damping cylinder 32, by supplying a control current to the proportional valve unit 36. The control arrangement 200 may thus be arranged in communication with the proportional valve unit 36 of the damping arrangement 30. The control arrangement 200 may be adapted to control the damping arrangement 30, such that pivotal movement about the articulation unit 8 is restricted or impeded. By restricting the pivotal movement about the articulation unit 8 the rear vehicle section 6 may not pivot in relation to the front vehicle section 4 when the braking force reduces the speed of vehicle 1. For this reason the rear vehicle section 6 may not pivot and move out of the direction of travel. If the rear vehicle section 6 should pivot and move out of the direction of travel, the rear vehicle section 6 may end up in the opposite lane, which may lead to a collision between the rear vehicle section 6 and an oncoming vehicle. Also, a jackknifing situation may be avoided by means of restricting the pivotal movement about the articulation unit 8.

The system 100 may further comprise means 230 for informing the operator of the vehicle 1 about the determination that the articulated vehicle is about to collide with an external object. The means 230 for informing the operator of the vehicle 1 may be arranged in communication with the control arrangement 200 via a link L230. The means 230 for informing the operator may comprise means for providing a visual alert to the operator. The means 230 for informing the operator may comprise means for providing an audial alert to the operator. The means 230 for informing the operator may comprise means for providing a tactile alert.

The control arrangement 200 of the system 100 may also be arranged in communication with other systems 240 of the vehicle 1. The control arrangement 200 may be arranged in communication with said other systems 240 via link L240. Such systems 240 may comprise an engine control system, a transmission control system or similar a steering wheel control system.

A computer 205 may also be arranged for communication with the control arrangement 200 via a link L205 and may be detachably connected to it. The computer 205 may be adapted to conduct the innovative method steps. The computer 205 may be used to cross-load software to the control arrangement 200, particularly software for conducting the innovative method. The computer 205 may alternatively be arranged for communication with the control arrangement 200 via an internal network on board the vehicle 1. The innovative method as described in connection to Fig. 3 may be conducted by the control arrangement 200 or the computer 205, or by both of them.

Fig. 3 illustrates a flow chart for a method for controlling an articulated vehicle 1 according to an embodiment. The vehicle 1 may be configured as the articulated vehicle 1 disclosed in Fig. 1 and thus comprises: a front vehicle section 4 and a rear vehicle section 6; an articulation unit 8 allowing the front vehicle section 4 and the rear vehicle section 6 to pivot in relation to each other; and a damping arrangement 30 arranged to control the pivotal movement about the articulation unit 8. The method comprises the steps of: a) determining if the articulated vehicle 1 is about to collide with an external object; and if so b) applying a braking force on the articulated vehicle 1; and c) controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 is restricted.

The method according to the invention may be performed by means of a system 100 for controlling an articulated vehicle 1 as disclosed in Fig. 2. The system 100 comprises a control arrangement 200, which may be adapted to perform the herein described method steps.

The step of determining if the articulated vehicle 1 is about to collide with an external object may be based on a detection of the external object by means of a first sensor element arranged on the articulated vehicle 1. Such sensor element may be arranged on the front part and rear part of the articulated vehicle 1. The first sensor element may be a radar arrangement, a LIDAR, a camera and/or a GPS sensor. The first sensor element may also be an ultrasonic proximity detector, an electromagnetic sensor, a blind spot monitor or the like. When the first sensor element detects the external object, information about the detection may be sent to an electronic control arrangement. The electronic control arrangement may process the information and determine if the articulated vehicle 1 is about to colliding with the external object. An operator of the vehicle 1 may be informed of the determination that the articulated vehicle 1 is about to collide with an external object. Such information to the operator or driver may be an indicating signal on instruments 44 in the driver's compartment 46. The indicating signal may be in form of a text message, a light signal, a sound signal and/or a haptic signal, such as vibrations conveyed to and sensed by the driver. The operator or driver may as a result of the information be prepared for the situation that the articulated vehicle 1 may collide with an external object. As a result, the operator may apply a braking force on the vehicle 1 in order to reduce the speed of vehicle 1 and stop the vehicle 1 before the vehicle 1 may collide with the external object. When the braking force is applied also the damping arrangement 30 may be controlled, such that pivotal movement about the articulation unit 8 is restricted.

The step of applying a braking force on the articulated vehicle 1 may be based on the determination that the articulated vehicle 1 is about to collide with an external object. When it is determined that the articulated vehicle 1 is about to collide with an external object the braking force acting on the articulated vehicle 1 may be applied automatically. The braking force may be applied by a brake arrangement acting on at least one wheel, on at least one drive axle and/or on a propeller shaft. The braking force may be automatically applied by means of an actuator acting on a braking pedal or directly on the brake arrangement acting on the at least one wheel, on the at least one drive axle and/or on the propeller shaft. Also, the braking force may be automatically generated by a propulsion source of the vehicle 1. The amount of the applied braking force may depend on the speed of the articulated vehicle 1, the weight of the articulated vehicle 1 ; the current load distribution of the articulated vehicle 1 and/or road condition. If the speed is high, the applied braking force may be high, so that the braking force may reduce the speed of vehicle 1 and stop the vehicle 1 before the vehicle 1 may collide with the external object. If the weight of the articulated vehicle 1 is high, the applied braking force may be high, so that the braking force may reduce the speed of vehicle 1 and stop the vehicle 1 before the vehicle 1 may collide with the external object. If the current load distribution of the articulated vehicle 1 is uneven, the amount of the applied braking force may be different for different wheels and drive axles, so that the braking force may effectively reduce the speed of vehicle 1 and stop the vehicle 1 before the vehicle 1 may collide with the external object. If the road condition is clean and free from snow or ice, the applied braking force may be high, so that the braking force may reduce the speed of vehicle 1 and stop the vehicle 1 before the vehicle 1 may collide with the external object. The speed of the articulated vehicle 1, the weight of the articulated vehicle 1 ; the current load distribution of the articulated vehicle 1 and/or road condition may be detected by means of a second sensor element.

The step of controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 is restricted may lead to that the rear vehicle section 6 may not pivot in relation to the front vehicle section 4 when the braking force reduces the speed of vehicle 1. For this reason the rear vehicle section 6 may not pivot and move out of the direction of travel. If the rear vehicle section 6 should pivot and move out of the direction of travel, the rear vehicle section 6 may end up in the opposite lane, which may lead to a collision between the rear vehicle section 6 and an oncoming vehicle. Also, a jack-knifing situation may be avoided by means of restricting the pivotal movement about the articulation unit 8. The controlling of the damping arrangement 30 may depend on the amount of the applied braking force. If the applied braking force is high, the damping arrangement 30 may be so controlled that the restriction of the pivotal movement about the articulation unit 8 is high. The high braking force applied on the articulated vehicle 1 may result in a high reduction of the speed of the vehicle 1. In order to avoid that the rear vehicle section 6 may pivot and move out of the direction of travel a high damping force applied on the articulation unit 8 by the damping arrangement 30 may restrict the pivotal movement about the articulation unit 8. Thus, both a jack-knifing situation may be avoided and a collision between the rear vehicle section 6 and an oncoming vehicle, due to that the rear vehicle section 6 may end up in the opposite lane, may be avoided. The damping arrangement 30 may be controlled to restrict the pivotal movement about the articulation unit 8 when the amount of the braking force is over a predetermined threshold value. The more braking force acting on the articulated vehicle 1, the more restriction of the pivotal movement about the articulation unit 8 may be needed in order to avoid a jack-knifing situation and/or a collision between the rear vehicle section 6 and an oncoming vehicle. However, if the braking force is at a level under a predetermined threshold value a pivotal movement about the articulation unit 8 may not appear during the speed reduction of the articulated vehicle 1. The threshold value may also depend on the the weight of the articulated vehicle 1, the current load distribution of the articulated vehicle 1 and/or road condition.

The articulation unit 8 may be a joint mechanism which connects the front vehicle section 4 and the rear vehicle section 6 and allows them to pivot in relation to each other. In order to be able to turn the vehicle 1 articulation about the articulation unit 8 may be required. A damping arrangement 30 comprising the damping element 32 may be arranged to reduce the horizontal movement between the front vehicle section 4 and the rear vehicle section 6. When no damping is provided, the front vehicle section 4 and the rear vehicle section 6 may pivot freely in relation to each other. With increased damping the pivotal movement about an articulation unit 8 may be restricted. With maximum damping pivotal movement about the articulation unit 8 may be more or less prevented. When restricting the operation of the articulated vehicle 1 the damping element 32 may be controlled, such that pivotal movement about the articulation unit 8 may be restricted, impeded or even prevented. Thus, the damping arrangement 30 may be controlled, such that the articulation unit 8 may become stiff/rigid. Thus, by controlling the damping arrangement 30 to restrict the pivotal movement, safety driving of the vehicle 1 may be increased.

The method may further comprise the step of d) controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 is allowed if an steering angle of a steering wheel 7 is detected. If the operator or driver of the vehicle 1 aims to avoid a collision with the external object by braking the articulated vehicle 1 and at the same time try to steer away from the externa object the damping arrangement 30 may be controlled so that the pivotal movement about the articulation unit 8 may be allowed. Otherwise, if the pivotal movement about the articulation unit 8 is restricted the turning ability of the articulated vehicle 1 may be restricted. Therefore, if a steering angle of a steering wheel 7 is detected during the braking force is applied on the articulated vehicle 1, the damping arrangement 30 may be controlled so that the pivotal movement about the articulation unit 8 may be allowed.

Fig. 4 is a diagram of a version of a device 500. The control arrangement 200 and/or computer 205 described with reference to Fig. 2 may in a version comprise the device 500. The term “link” refers herein to a communication link which may be a physical connection such as an optoelectronic communication line, or a non-physical connection such as a wireless connection, e.g. a radio link or microwave link. The device 500 comprises a non-volatile memory 520, a data processing unit 510 and a read/write memory 550. The non-volatile memory 520 has a first memory element 530 in which a computer programme, e.g. an operating system, is stored for controlling the function of the device 500. The device 500 further comprises a bus controller, a serial communication port, I/O means, an A/D converter, a time and date input and transfer unit, an event counter and an interruption controller (not depicted). The nonvolatile memory 520 has also a second memory element 540.

There is provided a computer programme Pr which comprises routines for controlling an articulated vehicle 1. The computer programme Pr comprises routines for determining if the articulated vehicle 1 is about to collide with an external object. The computer programme Pr comprises routines for applying a braking force on the articulated vehicle 1. The computer programme Pr comprises routines for controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 is restricted. The computer programme Pr comprises routines for controlling the damping arrangement 30, such that pivotal movement about the articulation unit 8 is allowed if a steering angle of a steering wheel 7 is detected.

The programme Pr may be stored in an executable form or in a compressed form in a memory 560 and/or in a read/write memory 550.

Where the data processing unit 510 is described as performing a certain function, it means that the data processing unit 510 effects a certain part of the programme stored in the memory 560 or a certain part of the programme stored in the read/write memory 550.

The data processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 511. The read/write memory 550 is adapted to communicating with the data processing unit 510 via a data bus 514.

When data are received on the data port 599, they are stored temporarily in the second memory element 540. When input data received have been temporarily stored, the data processing unit 510 is prepared to effect code execution as described above.

Parts of the methods herein described may be effected by the device 500 by means of the data processing unit 510 which runs the programme stored in the memory 560 or the read/write memory 550. When the device 500 runs the programme, methods herein described are executed.

The foregoing description of the embodiments is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

The components and features specified above may be combined between the different embodiments specified.

Claims (12)

1. A method for controlling an articulated vehicle (1), the articulated vehicle (1) comprising: a front vehicle section (4) and a rear vehicle section (6); an articulation unit (8) allowing the front vehicle section (4) and the rear vehicle section (6) to pivot in relation to each other; and a damping arrangement (30) arranged to control the pivotal movement about the articulation unit (8); the method comprising the steps of: a) determining if the articulated vehicle (1) is about to collide with an external object; and if so b) applying a braking force on the articulated vehicle (1); and c) controlling the damping arrangement (30), such that pivotal movement about the articulation unit (8) is restricted.

2. The method according to claim 1, wherein the determination if the articulated vehicle (1) is about to collide with an external object is based on a detection of the external object by means of a first sensor element arranged on the articulated vehicle (1).

3. The method according to any of claims 1 and 2, wherein the braking force is applied automatically.

4. The method according to any of the preceding claims, wherein the amount of the applied braking force depends on the speed of the articulated vehicle (1), the weight of the articulated vehicle (1); the current load distribution of the articulated vehicle (1) and/or road condition.

5. The method according to any of the preceding claims, wherein the controlling of the damping arrangement (30) depends on the amount of the applied braking force.

6. The method according to any of the preceding claims, wherein the damping arrangement (30) is controlled to restrict the pivotal movement about the articulation unit (8) when the amount of the braking force is over a predetermined threshold value.

7. The method according to any of the preceding claims, wherein the method further comprises to inform an operator of the vehicle (1) of the determination that the articulated vehicle (1) is about to collide with an external object.

8. The method according to any of the preceding claims, wherein method comprises the further step of: d) controlling the damping arrangement (30), such that pivotal movement about the articulation unit (8) is allowed if a steering angle of a steering wheel (7) is detected.

9. A computer program (Pr), wherein said computer program comprises programme code for causing a control unit (200; 500) or a computer (205; 500) connected to the control unit (200; 500) to perform the method according to any one of the preceding claims.

10. A computer-readable medium comprising instructions, which when executed by a control unit (200; 500) or a computer (205; 500) connected to the control unit (200; 500), cause the control unit (200; 500) or the computer (205; 500) to perform the method according to any one of claims 1-8.

11. A system (100) for controlling an articulated vehicle (1), the vehicle (1) comprising: a front vehicle section (4) and a rear vehicle section (6); an articulation unit (8) allowing the front vehicle section (4) and the rear vehicle section (6) to pivot in relation to each other; and a damping arrangement (30) arranged to control the pivotal movement about the articulation unit (8); wherein the system (100) comprises a control unit (200), the control unit (200) comprising: - means for determining if the articulated vehicle (1) is about to collide with an external object; and if so - means for applying a braking force on the articulated vehicle (1); and - means for controlling the damping arrangement (30), such that pivotal movement about the articulation unit (8) is restricted.

12. An articulated vehicle (1), comprising a system according to claim 11.